A turbine is placed in the center of the pipeline, and both ends are supported by bearings. When the fluid passes through the pipeline, it impacts the blades of the turbine flowmeter, generating a driving torque for the turbine flowmeter, and making the turbine flowmeter rotate against the friction torque and fluid resistance torque. In a certain flow range, for a fluid medium with a certain viscosity, the rotational angular velocity of the turbine flowmeter is directly proportional to the fluid velocity. Therefore, the fluid velocity can be obtained by the rotational angular velocity of the turbine flowmeter, so that the fluid flow through the pipeline can be calculated.

The rotating speed of the turbine flowmeter is detected by an induction coil installed outside the housing. When the blade of turbine flowmeter cuts the magnetic field lines generated by permanent magnet steel in the shell, it will cause the change of magnetic flux in the induction coil. The sensing coil sends the detected magnetic flux periodic change signal to the preamplifier, which generates a pulse signal proportional to the flow after amplification and shaping, and sends it to the unit conversion and flow integration circuit to obtain and display the accumulated flow value; At the same time, the pulse signal is also sent to the frequency-current conversion circuit, which converts the pulse signal into analog current and then indicates the instantaneous flow value.